Primitive Archer

Main Discussion Area => Bows => Topic started by: TurtleCreek on January 24, 2012, 11:28:23 am

Title: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 11:28:23 am
  Anyone ever try this with a hickory or bamboo back?
Title: Re: Compression strength of Bloodwood?
Post by: Pat B on January 24, 2012, 11:55:02 am
I have not but I would imagine hickory would be fine. I've made hickory backed red oak with good succss so if it istronger than red oak it shoul be OK for bloodwod.
Title: Re: Compression strength of Bloodwood?
Post by: footfootfoot on January 24, 2012, 12:22:02 pm
What is Bloodwood? There are a number of trees that go by this name. The one I am thinking of is what they use to make violin bows.
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 12:26:01 pm
The type I am referring to is Brosimum paraense, bloodwood, also referred to as "cardinal wood", a south american wood...  Sometimes listed as "Satine"
Title: Re: Compression strength of Bloodwood?
Post by: Bevan R. on January 24, 2012, 12:43:38 pm
I would think it would need a pretty good backing. It is heavy and dense. I got a board off the auction site, it is serious stuff. I think the SG is listed as almost 1 (if not more).
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 12:57:35 pm
  I thought it would make a beautiful bow and contrast nicely with a hickory or bamboo back
Title: Re: Compression strength of Bloodwood?
Post by: Bevan R. on January 24, 2012, 01:18:44 pm
I agree, it would be a beauty. If it was me, I would go with bamboo. I have not had much luck with hickory backing while I can't get stuff from Mr Gaskins.
Title: Re: Compression strength of Bloodwood?
Post by: footfootfoot on January 24, 2012, 01:36:29 pm
From http://www.wood-database.com/  <--- Be careful, you'll spend hours there.

Bloodwood:
Rupture Strength: 21,600 lbf/in2 (148,900 kPa)
Elastic Strength: 2,360,000 lbf/in2 (16,300 MPa)
Crushing Strength: 13,340 lbf/in2 (92.0 MPa)

For comparison:

Shagbark Hickory:
Rupture Strength: 20,200 lbf/in2 (139,310 kPa)
Elastic Strength: 2,160,000 lbf/in2 (14,900 MPa)
Crushing Strength: 9,210 lbf/in2 (63.5 MPa)

European Yew:
Rupture Strength: No data available: mostly likely very close to the bending strength for Pacific Yew, which is 15,200 lbf/in2 (104,830 kPa)
Elastic Strength: 1,320,000 lbf/in2 (9,100 MPa)
Crushing Strength: No data available: mostly likely very close to the crushing strength for Pacific Yew, which is 8,100 lbf/in2 (55.9 MPa)


Rupture Strength:
Also known as modulus of rupture (MOR), this is a measure of a specimen’s strength before rupture. It can be used to determine a wood species’ overall strength; unlike the modulus of elasticity (seen below) which measures the wood’s deflection, but not its ultimate strength. (That is to say, some species of wood will bow under stress, but not easily break.)
MOR is expressed in pounds-force per square inch (lbf/in2) or kilopaschals (kPa). This number is given for wood that has been dried to a 12% moisture content, unless otherwise noted.

In practical terms, the number itself isn’t all that meaningful, but it becomes useful to use in comparison with other woods. For instance, Hickory is known to have excellent strength properties among domestic species in the US, and has a MOR of 20,200 lbf/in2 (139,310 kPa). In comparison, Red Oak is another well-known wood used in cabinetry and furniture, and has a MOR of 14,300 lbf/in2 (98,620 kPa).

Elastic Strength:
In the most simple terms, the modulus of elasticity (MOE) measures a wood’s stiffness, and is a good overall indicator of its strength. Technically it’s a measurement of the ratio of stress placed upon the wood compared to the strain (deformation) that the wood exhibits along its length. MOE is expressed in pounds-force per square inch (lbf/in2) or megapaschals (MPa). This number is given for wood that has been dried to a 12% moisture content, unless otherwise noted.

In practical terms, the number itself isn’t all that meaningful, but it becomes useful to use in comparison with other woods. For instance, Hickory is known to have excellent strength properties among domestic species in the US, and has a MOE of 2,160,000 lbf/in2 (14,900 MPa). In comparison, Red Oak is another well-known wood used in cabinetry and furniture, and has a MOE of 1,820,000 lbf/in2 (12,500 MPa).
 

Crushing Strength:
Sometimes known as Compression Strength parallel to the grain, this is a measurement of the woods maximum crushing strength when weight is applied to the ends of the wood (compression is parallel to the grain). This number is a good indicator of the wood’s strength in applications such as deck posts, chair legs, or other circumstances where the load being applied is parallel rather than perpendicular to the grain.

In practical terms, the number itself isn’t all that meaningful, but it becomes useful to use in comparison with other woods. For instance, Ipe is known to have excellent strength properties among imported species, and has a crushing strength of 13,510 lbf/in2 (93.1 MPa). In comparison, White Oak is a well-known wood used in cabinetry and furniture, and has a crushing strength of 7,440 lbf/in2 (51.3 MPa), and Redwood is commonly used for decking, and has a crushing strength of 5,690 lbf/in2 (39.2 MPa).
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 01:40:45 pm
Wow, thanks footfootfoot!
Title: Re: Compression strength of Bloodwood?
Post by: Elktracker on January 24, 2012, 01:59:44 pm
John Strunk recently gave me a bamboo backed bloodwood and its one of my favorite shooting bows I love it and its a great combo too!!

Josh
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 02:54:02 pm
Elktracker, longbow ELB style?
Title: Re: Compression strength of Bloodwood?
Post by: Elktracker on January 24, 2012, 02:59:37 pm
Yes its a Bamboo Spirit longbow as always with John's bows its a work of art! But still a leathal weapon ;D I could post some pics if you want

Josh
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 24, 2012, 04:18:09 pm
Elktracker, that would be great. 
Title: Re: Compression strength of Bloodwood?
Post by: Elktracker on January 24, 2012, 04:33:27 pm
My camera does the bow little justice but here is what I have :D

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094607.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094642.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094654.jpg)


(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094840.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094912.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094945.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_095102.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_095422.jpg)

(http://i1019.photobucket.com/albums/af314/mandoman1540/IMG_20120124_094926.jpg)

This is the most accurate bow I own and I really enjoy shooting it! no one around for a full draw but its perfect I assure you!
Josh
Title: Re: Compression strength of Bloodwood?
Post by: footfootfoot on January 24, 2012, 05:35:27 pm
That is gorgeous. Astounding how delicate looking the nocks are.
Title: Re: Compression strength of Bloodwood?
Post by: Stiks-N-Strings on January 24, 2012, 05:38:13 pm
Turtle, I built one and it would have been a fantastic shooter I assume. It blew up due to starving the glue joint in the fade area. I would build it just like a boo backed osage. and be careful not to starve the glue joint LOL
Title: Re: Compression strength of Bloodwood?
Post by: Elktracker on January 24, 2012, 05:44:43 pm
I agree footfoot he does amazing work! This bow was built in 2004 and shoots like a dream like all of Johns bows! I about crapped my pants when he picked it out of his pile of bows and handed it to me and told me it was mine after I told him how beautiful it was. :o

Josh
Title: Re: Compression strength of Bloodwood?
Post by: footfootfoot on January 24, 2012, 05:50:02 pm
Ha! Elktracker. I'll remember to bring a change of underwear if I ever meet him and visit his shop.
Title: Re: Compression strength of Bloodwood?
Post by: soy on January 24, 2012, 09:58:15 pm
Thanks for bringing another wood I need to obtain into view >:( man that bow is breathtaking I would love to see it in person :o
Title: Re: Compression strength of Bloodwood?
Post by: TurtleCreek on January 25, 2012, 06:01:26 am
Sweet lookin' bow, thanks for the pics